Question: Subtract. $\dfrac{9}{3} - \dfrac{8}{12} = $
Before we can subtract our fractions, they need to have the same denominator. $\dfrac{9}{3}$ $\dfrac{8}{12}$ $\dfrac{9}{3}-\dfrac{8}{12}$ Let's look at the multiples of each denominator and see which multiples they have in common. Denominator Multiples ${3}$ $3, {6}, 9, \underline{12}, 15$ $12}$ $\underline{12},24, 36$ The least common denominator is ${12}$. Let's use multiplication to make each fraction have a denominator of $12$. ${\dfrac{9}{3}}=\dfrac{{9} \times {4}}{{3} \times {4}} = {\dfrac{36}{12}}$ Now, we can subtract ${\dfrac{36}{12}} - \dfrac{8}{12}}$. $\dfrac{36}{12}$ $\dfrac{8}{12}$ $\dfrac{36}{12} - \dfrac{8}{12}$ $=\dfrac{{36}-8}}{12}$ $= \dfrac{28}{12}$ ${\dfrac{9}{3}} - \dfrac{8}{12}} = \dfrac{28}{12}$ We can also write $\dfrac{28}{12}$ as $\dfrac{7}{3}$ or $2\dfrac{1}{3}$.